Amplifiers are used for a variety of purposes. For example, a sense amplifier may be used to measure current. A voltage generated across a low resistance value sense resistor is a function of the current through the resistor. The voltage across the sense amplifier is amplified by a sense amplifier and may be used in a control feedback loop. For example, the sense amplifier may be part of a motor controller device and the current through the motor is used as a feedback signal to help control the speed of the motor.
Amplifiers may have any a wide variety of architectures. Some amplifiers, for example, have an asymmetric architecture. An asymmetric amplifier is one in which the circuitry differs for signal flow of each input-to-output. For example, if the amplifier is a differential amplifier having a positive input and a negative input, the input circuitry of the positive input is configured differently than the input circuitry of the negative input. Because of such asymmetry, as well as device modelling inaccuracies, parasitic effects, and semiconductor process variations, the common mode gain of the amplifier may be higher than the value that is acceptable for various applications.